Fix new branch dropdown position and size -- EE merge edition

Closes gitlab-ce#32096

See merge request !1875

Geo: Resync repositories that have been updated recently

See merge request !1826

Remove trailing comma

See merge request !1882

Security patches -> EE `master`

See merge request !1864

Improve Repository Sync (with new SystemHook)

Closes #1463 and #1493

See merge request !1789

Fix slash commands detection in comments

See merge request !1876

Fix flickering of system notes -- EE merge edition

Closes gitlab-ce#32087

See merge request !1873

Use new Commit#raw_deltas method

See merge request !1854

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/32096

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/32087

Easy reproduction:

 1. Edit an issue title
 1. Notice the system note added
 1. Switch to another tab and back (to fire the polling immediately)
 1. Notice the flicker (without this fix)

[EE] Resolve "Use consistent style for trailing commas"

See merge request !1796

Make all Serializers receive `current_user` instead `user` [EE]

See merge request !1869

Port of 32077-pipeline-graph-margins to EE

See merge request !1867

Use the EnforcedStyleForMultiline: no_comma option.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Use the EnforcedStyleForMultiline: no_comma option.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Feature availability check using feature list AND license addons

See merge request !1851

New Hamlit XSS fix, does not include extraneous changes

See merge request !509

Respect project features when searching alternative branches with elasticsearch enabled

See merge request !508

Use GroupsFinder to find subgroups the user has access to

See merge request !2096

New Hamlit XSS fix, does not include extraneous changes

See merge request !2095

Refactor snippets finder & dont return internal snippets for external users

See merge request !2094